This choice of is a relatively modern move, which became quite popular in the 1990s. Its aim is to get sente. A black stone at a is more or less required, but in this joseki it is almost always present anyway. White invariably answers at 2. Black 3 next is the proper move; Black b is a bit of an overplay. After this, White can choose between c and d.
As stated above, is an overplay. Although the white group is confined to the corner after
, the aji of White a is unpleasant for Black.
was played by Chang Hao against Ma Xiaochun in the 1999 Qisheng match. As in the other variations of this joseki, Black's intention was to get a wall in sente.
is the most common continuation after
. The continuation to
is joseki, after which White will either secure the position with
or play tenuki. There exist examples of Black playing
at
, leaving aji at the top in exchange for more influence in the center.
If White does not play at in the previous diagram,
is not sente: White cannot be killed. But capturing a stone in sente with
and
of course gives Black a very strong position, while the white corner is reduced to about 5 points.
If White does play the marked stone, Black will not answer it - if Black does intend to answer it, Black would have done better to play the old variation. White's follow-up will probably be and
here. This also shows why the
stone is important. Without it, White would play the double hane at
rather than
, which would not be to Black's liking.
White's second option is to play at immediately, without first playing hane at
and connecting. White will however have to take the possibility of
in account - this is not a small move. This variant was played between Hane Yasumasa (Black) and Fujisawa Hideyuki in the 1991 Oza match.
Author: Andre Engels